| /* Copyright (C) 2010-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <pwd.h> |
| #include <unistd.h> |
| #include <not-cancel.h> |
| |
| #define STATIC static |
| static int getlogin_r_fd0 (char *name, size_t namesize); |
| #define __getlogin_r getlogin_r_fd0 |
| #include <sysdeps/unix/getlogin_r.c> |
| #undef __getlogin_r |
| |
| |
| /* Try to determine login name from /proc/self/loginuid and return 0 |
| if successful. If /proc/self/loginuid cannot be read return -1. |
| Otherwise return the error number. */ |
| |
| int |
| attribute_hidden |
| __getlogin_r_loginuid (char *name, size_t namesize) |
| { |
| int fd = __open_nocancel ("/proc/self/loginuid", O_RDONLY); |
| if (fd == -1) |
| return -1; |
| |
| /* We are reading a 32-bit number. 12 bytes are enough for the text |
| representation. If not, something is wrong. */ |
| char uidbuf[12]; |
| ssize_t n = TEMP_FAILURE_RETRY (__read_nocancel (fd, uidbuf, |
| sizeof (uidbuf))); |
| __close_nocancel_nostatus (fd); |
| |
| uid_t uid; |
| char *endp; |
| if (n <= 0 |
| || n == sizeof (uidbuf) |
| || (uidbuf[n] = '\0', |
| uid = strtoul (uidbuf, &endp, 10), |
| endp == uidbuf || *endp != '\0')) |
| return -1; |
| |
| /* If there is no login uid, linux sets /proc/self/loginid to the sentinel |
| value of, (uid_t) -1, so check if that value is set and return early to |
| avoid making unneeded nss lookups. */ |
| if (uid == (uid_t) -1) |
| { |
| __set_errno (ENXIO); |
| return ENXIO; |
| } |
| |
| size_t buflen = 1024; |
| char *buf = alloca (buflen); |
| bool use_malloc = false; |
| struct passwd pwd; |
| struct passwd *tpwd; |
| int result = 0; |
| int res; |
| |
| while ((res = __getpwuid_r (uid, &pwd, buf, buflen, &tpwd)) == ERANGE) |
| if (__libc_use_alloca (2 * buflen)) |
| buf = extend_alloca (buf, buflen, 2 * buflen); |
| else |
| { |
| buflen *= 2; |
| char *newp = realloc (use_malloc ? buf : NULL, buflen); |
| if (newp == NULL) |
| { |
| result = ENOMEM; |
| goto out; |
| } |
| buf = newp; |
| use_malloc = true; |
| } |
| |
| if (res != 0 || tpwd == NULL) |
| { |
| result = -1; |
| goto out; |
| } |
| |
| size_t needed = strlen (pwd.pw_name) + 1; |
| if (needed > namesize) |
| { |
| __set_errno (ERANGE); |
| result = ERANGE; |
| goto out; |
| } |
| |
| memcpy (name, pwd.pw_name, needed); |
| |
| out: |
| if (use_malloc) |
| free (buf); |
| |
| return result; |
| } |
| |
| |
| /* Return at most NAME_LEN characters of the login name of the user in NAME. |
| If it cannot be determined or some other error occurred, return the error |
| code. Otherwise return 0. */ |
| |
| int |
| __getlogin_r (char *name, size_t namesize) |
| { |
| int res = __getlogin_r_loginuid (name, namesize); |
| if (res >= 0) |
| return res; |
| |
| return getlogin_r_fd0 (name, namesize); |
| } |
| libc_hidden_def (__getlogin_r) |
| weak_alias (__getlogin_r, getlogin_r) |
| libc_hidden_weak (getlogin_r) |